This invention relates to cushioning devices for footwear.
Stubblefield, U.S. Pat. No. 4,372,058, describes a shoe sole having a tread which defines a longitudinally and/or laterally oriented concavity. The lower extremities of the sole are formed by downwardly and outwardly disposed flexible lugs which cushion the foot of a wearer against impact loads. Stubblefield, U.S. Pat. No. 4,449,307, describes a basketball shoe sole having a central longitudinally arranged support wall.
Parracho et al., U.S. Pat. No. 4,402,146 disclose a sole having side tabs extending from the outsole to the shoe upper. These tabs are designed to stabilize the midsole and reduce ankle fatigue.
Stirtz et al., U.S. Pat. No. 4,297,796, describe an inner sole member formed of an open mesh web. The web includes elongated interwoven stretch resistant strands disposed at oblique angles relative to the longitudinal axis of the shoe. The strands act as force transmitters with respect to the sole member.
Bowerman et al., U.S. Pat. No. 4,128,950, describe a multilayered athletic shoe sole formed of synthetic plastic foam positioned between a hard outsole and an upper. A lateral extending heel stabilizer plate of solid plastic material is added to improve lateral stability.
Fowler, U.S. Pat. Nos. 4,451,994 and 3,834,046 disclose various designs for a midsole, e.g., replacing a conventional cushioning midsole foam with a ribbed, resilient, internal diaphragm.
Kosava, U.S. Pat. No. 4,492,046 describes a running shoe having a longitudinal slot in its sole in which an internal spring wire is inserted.
Crowley, U.S. Pat. No. 4,881,329 describes an athletic shoe having an internal spring in its midsole.
Weber, U.S. Pat. No. 4,566,206 describes an internal spring provided in a heel of a shoe.
Jacinto, U.S. Pat. No. 4,592,153 describes internal Z-shaped plates within the heel or other portions of a shoe.
Schuster, DE3415-705-A describes a wire spring arrangement under a shoe sole.
Mintzer, U.S. Pat. No. 224,937 describes an engineer's shoe having a spring.
Horten, U.S. Pat. No. 2,953,861 describes resilient jumping shoes.
Hannemann, U.S. Pat. No. 4,771,554 describes an internal heel insert.
Barbeau, FR 2507-066 describes a spring in the sole of a training shoe.
Schnell, EP103-041-A describes a sports shoe with a spring sole.
Lindh et al., U.S. Pat. No. 4,910,884 describes a shoe sole having a spring apparatus.
Spademan, U.S. Pat. Nos. 4,546,555 and 4,924,605 describe shoes having shock absorbers.